Recently, in the field of endoscope, a capsule endoscope equipped with an imaging function and a radio communication function has appeared. This capsule endoscope has a configuration of moving in the internal organs (body cavity) such as esophagus, stomach, and small intestine with peristalsis during an observation period after it is swallowed from a mouth of an examinee as a subject of observation (examination) until it is naturally discharged from a living body (human body) of the examinee, and sequentially taking pictures at a predetermined imaging rate by using the imaging function.
During this observation period while the endoscope is moving in the internal organs, image data acquired in the internal organs by the capsule endoscope is sequentially transmitted to the outside of the examinee by the radio communication function such as radio communications, and stored in a memory provided in an external receiving device. If the examinee carries the receiving device having the radio communication function and the memory function, the examinee swallows the capsule endoscope and then can freely move without any inconvenience even during the observation period until the endoscope is discharged (see Patent Document 1).
When the image data is received, generally in the receiving device, a plurality of antennas is distributed and arranged outside of the examinee for receiving an image signal transmitted from the capsule endoscope, and one antenna having a strong received strength is selected and changed over, to receive the image signal. For example, a receiving device is described in Patent Literature 1, which switches reception of antennas arranged outside of the examinee, to detect the position of the capsule endoscope in the examinee, which is a transmission source of the image signal, based on an electric field strength received by each antenna.
In such a capsule endoscope system, after a series of an imaging operation by the capsule endoscope has been completed, the image data stored in the memory of the receiving device is generally transferred to a workstation or the like, and examination of the image is performed afterwards. However, there are strong demands from doctors for real-time examination of the images of sites such as esophagus and stomach or concerned sites, since the capsule endoscope passes these sites within short time. A system including a simplified image display apparatus that displays images on a real-time basis based on the radio signal transmitted from the capsule endoscope has also been proposed.
A conventional simplified image display apparatus has a configuration capable of electrically connecting to the receiving device, as the simplest configuration, and includes a small display unit and a predetermined signal processor. By having such a configuration, the simplified image display apparatus can input a signal having subjected to reception processing by the receiving device, and after having performed predetermined processing based on the input signal, the simplified image display apparatus displays images taken by the capsule endoscope on the small display unit.
Patent Document 1: Japanese Patent Application Laid-open No. 2003-19111